The purpose of this proposal is to document that the Adolescent Medicine Clinic of the University of Maryland Medical Systems has the necessary components to be a participant in a cooperative, multi-site study of adolescents who are infected with the HIV virus. Specifically, the Adolescent Clinic has: 1) a broad base of adolescent patients (12-19 years) who are at high risk of contracting the HIV virus; 2) an existing clinic devoted to the evaluation and care of adolescents who are HIV+ with existing clinical care protocols in place; 3) at least 27 HIV+ adolescents identified and followed by the Adolescent Clinic; 4) an interdisciplinary team of care givers experienced in the care of adolescents in general, and high risk adolescents in particular and experienced and active in interdisciplinary research; 5) a close collaborative relationship with the Pediatric AIDS program in the Division of Allergy/Immunology; a participating ACTG site for the last five years 6) an extensive outreach program for referrals of additional HIV+ adolescents from other university sites and the community; and 7) designation by the state of Maryland as the only state approved Diagnostic and Evaluation Unit for HIV+ adolescents who are on Medicaid. The UMMS Adolescent Clinic is a well established program and is recognized as one of the pioneer programs for adolescent health care in the US. Because all of the above components are in place and have been in place for more than 20 years, the Adolescent Medicine Clinic is an optimal setting for participation in a multi-site study.